The temperature of a sample of water changes from 10°c to 20°c when the sample absorbs 418 joules of heat. what is the mass of the sample?
(1) 1 g (3) 100 g
(2) 10 g (4) 1000

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Answer asap need to be answered by wednesday morning explain how a buffer works, using an ethanoic acid / sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.

The kw for water at 0 °c is 0.12× 10–14 m2. calculate the ph of a neutral aqueous solution at 0 °c.